To the White House, former spokesman Scott McClellan’s criticism of his old boss may taste as bitter as cranberry sauce without any sugar. To Democratic presidential candidates, it’s as sweet as a slice of pecan pie.

McClellan, who served as Bush’s press secretary from 2003 to 2006, said Tuesday the president was “involved” in spreading false information about the leak of a CIA officer’s identity, an action that ultimately resulted in a perjury conviction for top White House aide Lewis “Scooter” Libby.

The White House denied that Bush had asked anyone to pass on false information. But McClellan’s comments, excerpted from an upcoming memoir, come as another blow for an administration that has suffered rock-bottom approval ratings and an exodus of top aides in recent months.

One day before Thanksgiving, Democratic presidential candidates feasted on the news.

Delaware Sen. Joseph Biden said Bush’s alleged behavior was “outrageous” and called on the president to explain himself.

Connecticut Sen. Chris Dodd said the Justice Department should investigate.

“If in fact the President of the United of States knowingly instructed his chief spokesman to mislead the American people, there can be no more fundamental betrayal of the public trust,” Dodd said.

And New Mexico Gov. Bill Richardson? “Rare Truth from a White House Flack: Bush Lies,” read the headline on his press release.

It looks like all three candidates are treating McClellan’s comments like a big bowl of mashed potatoes that could give them the boost they need to catch frontrunners Hillary Clinton, Barack Obama and John Edwards before the primaries start in January.

But they likely can’t count on a second helping from McClellan. His memoir isn’t due out until April, well after most states hold their primaries.